Air filter comparisons?

I've heard to NEVER use a K&N filter on more than one occasion. I've
recently been told that especially in high dust areas that they are
especially bad.

What are the filtering facts on these? particle size filtered? I saw
something about 10-20 microns on their site being bad for a motor, but
didn't see anything about what they have the ability to filter.
I own a K&N, but don't have it installed. I have a WIX where that K&N is to
fit. I've been told that AFE filters, similar to the kn style are a much
better product, but don't have facts on those, either.
Can someone offer up information of links to find this information?
Thanks,
Snowman

I got a k&n with my Banks system for my 6.5 TD and ran it for a while until
a guy I got some turbo parts from told me to get it out because the dirt
will begin to eat away at the prevailing edges of the turbo fins. I did,
indeed, put my WIX back in.

to
Snow,
Aside from the fact that they allow hella dirt into your motor, the
"performance" benefit isn't even there. I did the math on the ng a few
months back. Essentially the extra cfm's the K&N flows over paper can't
even be used by a naturally aspirated engine. The paper elements already
flow more cfm's than a naturally aspirated engine can suck in; the extra 400
cfm's the K&N flows are just useless.
Doc

K&N cannot comment on tests conducted by this person since we have no way to
confirm or validate his statements about how he performed them (or if in
fact he did).
We can only tell you our findings when we had our filters tested.
Our filters are tested by an outside, independent laboratory. They have
been proven to stop at least 99% of particles on a SAE dust test. This test
uses particles as low as the 0 - 5 micron range and goes up to 20 microns.
For comparison, a paper filter also stops 99% on the same test and the OEM
minimum standard is 96%. Foam is generally the worst media with a typical
efficiency rating of 75 - 85%.
The testing procedure used is SAE J-726 using ISO Test Dust. This test is
the standard of the air filter industry. The test procedure consists of
flowing air through the filter at a constant rate (airflow rate is
determined by the application) while feeding test dust into the air stream
at a rate of 1 gram per cubic meter of air. Links to the filtration tests
are on our web site at

http://www.knfilters.com/images/factstab1.gif
and

http://www.knfilters.com/images/factstab2.gif
As the filter loads with dust the pressure drop across the filter is
increased to maintain the prescribed airflow rate. The test is continued
until the pressure drop increases 10" H2O above the initial restriction of
the clean element (in this case .78" to 10.78" H2O). At this point the test
is terminated. The dirty filter element is then weighed. This weight is
compared to the clean element weight to determine the total Dust Capacity.
The amount of dust retained by the filter is divided by the total amount of
dust fed during the test to determine the Cumulative Efficiency.
The K&N filter achieved the following results:
Dust Capacity: 305 grams
K&N Cumulative Efficiency: 99.05 %
K&N Initial Pass Efficiency: 97.11 %
OEM Paper Cumulative: 99.29 %
OEM Paper Initial Pass: 96.47 %
Holding the filter to the light is useless, pin holes are normal. That is
what makes a K&N filter. There are actually dozens of microscopic fibers
that cross these holes that when treated with oil become somewhat
transparent but still capture and hold the very fine particles. Spray WD-40
on a piece of paper and it will be transparent too. On the same hand, they
allow the filter to flow more air than paper or foam. The filter is 4 ply
cotton gauze unlike some competitors synthetic material filters. The
synthetics do not have the very small fibers that natural cotton does.
Also, the oil can be pulled off of a foam filter contaminating electronic
sensors. It will absorb into cotton and stay in the media.
We got started over 30 years ago making filters for motorcycles and off road
racers. The filters did so well that these guys wanted them for their cars
and trucks. We started making filters for these applications and here we
are today. If they did not work, we would not still be here and growing
every year.
We now make filters for Chrysler/Mopar, Ford Motorsports, Edelbrock, Rotax
Engines, and Harley Davidson. We come as original equipment on the 2000
Ford Mustang Cobra-R. We even made filters for the Apache helicopters used
in Desert Storm because of maintenance problems with the original paper
design. Now we are on the new unmanned Predator plane being used in
Afghanistan.
I hope this answers any question you have about our filters ability to
perform.
Customer Service
K&N Engineering, Inc.
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it to any other person, copy or distribute it or use it for any purpose.

really
Put it this way, the extra CFM's your K&N flows can't be used by the engine
anyways. Paper filters flow around 15% more than a stock engine can use,
K&N's around 55% more cfm's than can be used. So if it's a matter of
performance, they do nothing, and if there is even a hint that they don't
filter all that well, I'd be yankin' it.
Doc

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